The immediate goal of the proposed research is to learn more about the operating characteristics of the three principal phenomena of binocular vision--stereopsis, binocular rivalry, and binocular combination or fusion. Three related lines of inquiry are proposed, each dealing with one of the three principal phenomena. The method of investigation is the psychophysical paradigm, wherein considerable data are obtained from a relatively small number of human observers. The research on stereopsis is concerned with the way in which depth information is extracted from random-element stereograms and focuses upon the interaction of stereoscopic and physical contours, the contribution of cognitive variables to enhance the perception of stereopsis, the role of experience in perceiving stereopsis, and methods for assessing stereopsis in infants and young children. The research on binocular rivalry is designed to specify more precisely the kind of information that is lost during rivalry suppression and the relationship between rivalry suppression and the kind of suppression associated with binocular anomalies such as strabismus. The research on binocular combination attempts to test the hypothesis that suppression might be operative during the ostensibly cooperative fusion states of normal binocular viewing. The long-range objective of the program is to contribute information that would aid in the development of a general theory of binocular vision that would encompass stereopsis, rivalry, and binocular combination in a single framework. Moreover, the research has implications for both the etiology and the treatment of binocular visual anomalies in humans.